> On 06/18/2010 12:42 PM, Andres Salomon wrote:> > +> > + /* install OFW's PDE permanently into the kernel's pgtable */> > + set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);> > + flush_tlb();> > + early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);> > I just realized... this flush_tlb() is actually not necessary since on x86 > it is always legal to go from a less permissive configuration to a more > permissive, and the initial configuration is "not present" which is > maximally nonpermissive.> > Could you take it out and make sure it still works?

small nit: an optimization barrier would still be needed if the result is being relied on by the kernel.